Malaria is a life-threatening mosquito-borne blood disease caused by a Plasmodium parasite, transmitted to humans through the saliva of an infected female Anopheles mosquito. Only female mosquitoes feed on blood; male mosquitoes feed on plant nectar and do not transmit the disease.

Once the parasites are inside your body, they travel to the liver, where they mature. After several days, the mature parasites enter the bloodstream and begin to infect red blood cells.

Within 48 to 72 hours, the parasites inside the red blood cells multiply, causing the infected cells to burst open.

The parasites continue to infect red blood cells, resulting in symptoms that occur in cycles that last two to three days at a time.

The symptoms of malaria typically develop within 10 days to 4 weeks following the infection. In some cases, symptoms may not develop for several months. Some malarial parasites can enter the body but will be dormant for long periods of time.

Common symptoms of malaria include:

• shaking chills that can range from moderate to severe
• high fever
• profuse sweating
• headache
• nausea
• vomiting
• abdominal pain
• diarrhea
• anemia
• muscle pain
• convulsions
• coma
• bloody stools

IT’s Prevention and Treatment

There is currently no vaccine for the prevention of Malaria although preventive anti-malaria medications are the same as those used to treat the disease and should be taken at intervals before symptoms manifest.

Talk to your doctor about long-term prevention if you live in an area where malaria is common, such as sub-Saharan Africa (Burkina Faso, Cameroon, Democratic Republic of the Congo, Ghana, Mali, Mozambique, Niger, Nigeria, Uganda and United Republic of Tanzania) and India. Sleeping under a mosquito net may help prevent being bitten by an infected mosquito. Covering your skin or using bug sprays containing DEET] may also help prevent infection.

The geographic distribution of malaria

The term malaria originates from Medieval Italian: mala aria—”bad air”; the disease was formerly called ague or marsh fever due to its association with swamps and marshland.

Malaria is prevalent in tropical and subtropical regions because of rainfall, consistent high temperatures and high humidity, along with stagnant waters in which mosquito larvae readily mature, providing them with the environment they need for continuous breeding. In drier areas, outbreaks of malaria have been predicted with reasonable accuracy by mapping rainfall. Malaria is more common in rural areas than in cities. For example, several cities in the of Southeast Asia are essentially malaria-free, but the disease is prevalent in many rural regions, including along international borders and forest fringes. In contrast, malaria in Africa is present in both rural and urban areas, though the risk is lower in the larger cities. Malaria was once common in most of Europe and North America, where it is no longer endemic, though imported cases do occur.

Human survival mechanisms a natural form of resistance

Recent bioinformatics analysis of changes in human ecology suggest that about 6,000 years ago, P. falciparumpopulations expanded rapidly in Africa and spread worldwide, coincident with human population growth and subsequent diasporas facilitated by the dawn of agriculture. This parasite has exacted a heavy mortality toll on Africa’s population, evidenced by the selection for several human survival mechanisms, such as the genetic polymorphisms associated with red cell structure and function. Malaria infection is common in Sub-Saharan Africa, but death directly attributed to the parasite is comparatively rare, largely because of acquired functional immunity. Unlike the human immunodeficiency virus (HIV) and the acquired immune deficiency syndrome (AIDS) or tuberculosis, infection with the malaria parasite is almost always universal in a population, and the presence of the pathogen is not a sufficient marker of disease. Individuals who die from malaria represent the public health costs of developing immunity at a population level. These deaths are concentrated among those with poorly developed immunity, and, generally, young children bear the brunt of the mortality burden. Individuals born into areas of stable P. falciparum transmission frequently acquire and clear infections without becoming ill, but most will, at some stage in their lives, develop an overt clinical response to infection, often manifested as fever. These clinical events may lead to severe complications, which may resolve naturally, require medical intervention, or result in death.

Many individuals naturally acquire functional immune responses to severe disease and death early in life; immunity to the milder consequences of infection occurs later in childhood, but the ability to sterilize blood-stage infection probably does not occur until adulthood. The relation between the frequency of parasite exposure and disease outcome is complex. The speed with which a population acquires functional immunity to the severe consequences of P. falciparum infection depends on the frequency of parasite exposure from birth as measured by the intensity of parasite transmission in a given locality. Where infection is rare the risk of mortality is likely to be directly related to the risk of infection, because acquired functional immunity is unlikely to affect health outcomes. Understanding this relationship is important for defining the age-specific mortality burdens in Sub-Saharan Africa.

Credit:

www.ncbi.nlm.nih.gov

en.wikipedia.org

www.healthline.com